Synthesis of poly(acrylamide)-based hydrogel for bio-sensing of hepatitis B core antigen

The major health issues posed by hepatitis B virus (HBV) globally have always been the impetus for the development of novel diagnostic assays. Here, we report the synthesis of bio-conjugated polyacrylamide-based hydrogel (HBPAAm hydrogel) that responds to the presence of hepatitis B core antigen (HBcAg) by a weight change in the hydrogel. The HBPAAm hydrogel contained the affinity crosslinks formed by the bio-specific coupling between the bound HBcAg and its antibody (anti-HBc). In the presence of analyte (i.e., free HBcAg), the immobilized HBcAg-(anti-HBc) complexes in HBPAAm hydrogel were disrupted; the competitive binding of free HBcAg onto the bound anti-HBc in HBPAAm hydrogel triggered the swelling of hydrogel. The swelling of HBPAAm hydrogel corresponded to the concentration of free HBcAg. The bio-sensing property of HBPAAm hydrogel is highly specific, and the reusability of HBPAAm hydrogel for multiple runs of HBcAg sensing was demonstrated. The bio-conjugated hydrogel has great potential as a sensing component of the biosensor that allows the detection of HBV serological markers at a lower cost and a shorter time.